Injection molding apparatus and method for automatic cycle to cycle cavity injection

ABSTRACT

An injection molding system comprising:a first selected valve,one or more downstream valves, delivering a fluid to a mold cavity,at least one fluid property sensor that detects a flow front of fluid material flowing downstream through the mold cavity at a trigger location within the cavity disposed between the first gate and at least one selected downstream gate,a controller instructing an actuator associated with the downstream gates to open the gates at a predetermined open gate target time on a first injection cycle,each valve associated with a position sensor that detects opening of a gate at an actual open gate time to the controller,the controller automatically adjusting time of instruction to open the gates on a subsequent injection cycle by an adjustment time equal to any delay in time between the predetermined open gate target time and the actual open gate time.

RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityto U.S. application Ser. No. 15/724,550 filed on Oct. 4, 2017, which inturn is a continuation of and claims the benefit of priority toPCT/US17/043029 filed Jul. 20, 2017 which in turn claims the benefit ofpriority to U.S. Application Ser. No. 62/364,488, filed 20 Jul. 2016 thedisclosures of which are incorporated by reference as if fully set forthin their entirety herein.

The disclosures of all of the following are incorporated by reference intheir entirety as if fully set forth herein: U.S. Pat. Nos. 5,894,025,6,062,840, 6,294,122, 6,309,208, 6,287,107, 6,343,921, 6,343,922,6,254,377, 6,261,075, 6,361,300 (7006), U.S. Pat. Nos. 6,419,870,6,464,909 (7031), U.S. Pat. Nos. 6,599,116, 7,234,929 (7075US1), U.S.Pat. No. 7,419,625 (7075US2), U.S. Pat. No. 7,569,169 (7075US3), U.S.patent application Ser. No. 10/214,118, filed Aug. 8, 2002 (7006), U.S.Pat. No. 7,029,268 (7077US1), U.S. Pat. No. 7,270,537 (7077US2), U.S.Pat. No. 7,597,828 (7077US3), U.S. patent application Ser. No.09/699,856 filed Oct. 30, 2000 (7056), U.S. patent application Ser. No.10/269,927 filed Oct. 11, 2002 (7031), U.S. application Ser. No.09/503,832 filed Feb. 15, 2000 (7053), U.S. application Ser. No.09/656,846 filed Sep. 7, 2000 (7060), U.S. application Ser. No.10/006,504 filed Dec. 3, 2001, (7068) and U.S. application Ser. No.10/101,278 filed Mar. 19, 2002 (7070) and PCT application no.PCT/US2011/029721 filed Mar. 24, 2011 (7094), PCT publication no.WO2012074879 (A1) (7100WO0) and WO2012087491 (A1) (7100W01) andPCT/US2013/75064 (7129WO0) and PCT/US2014/19210 (7129WO1) andPCT/US2014/31000 (7129WO2).

FIELD OF THE INVENTION

The present invention relates to injection molding systems and methods,and more particularly to a system and method for triggering and timingthe opening of valve pins in a sequential valve gate process.

BACKGROUND OF THE INVENTION

Injection molding systems that feature sequential opening of multiplegates to a single mold cavity provide significant advantages to themolding of large scale parts, such as automobile body parts. Thebenefits of sequential valve gating depend upon the sequential timingbetween the upstream and downstream gates, so that the melt flows fromeach gate coalesce into a single smooth flow stream in the cavity.Otherwise, air bubbles or surface defects in the molded part will occur.

SUMMARY OF THE INVENTION

In various embodiments, the invention relates to an apparatus and methodfor triggering the opening of multiple gates to a single mold cavity ofan injection molding system. In contrast to the prior art valve gatingsystems that depend on a preset time or screw position, in oneembodiment the present invention utilizes a new apparatus and method oftriggering based on flow front detection in the cavity coupled withdetection by position sensors of the actual time of valve pin withdrawalfrom the respective gate. In another embodiment the invention utilizestriggering based on a start of injection cycle or a position of a screwbarrel that feeds fluid material to an injection molding system, coupledwith detection by position sensors of the actual time of valve pinwithdrawal from the respective gate. These embodiments enable automaticadjustments to be made on subsequent injection cycles. The inventionthus facilitates automatic set-up, monitoring and/or adjustment of thesequential valve gating process and reduces the need for highlyexperienced operators.

In accordance with the invention there is provided an injection moldingsystem (10) for initiating flow of fluid material (4) into multiplegates of a mold cavity (18) during an injection molding cycle, thesystem (10) comprising:

a first selected valve comprising a first fluid flow passage (22C)having a first gate (24C) to the cavity, a first valve pin (26C) drivenreciprocally along an axial upstream downstream path of travel throughthe first flow passage (22C) by a first actuator (30C) between gate openand gate closed positions,

one or more downstream valves, each downstream valve comprising adownstream fluid flow passage (22A, 22B, 22D, 22E) having a downstreamgate (24A, 24B, 24D, 24E) to the cavity (18) disposed downstream of thefirst gate (24C), a downstream valve pin (26A, 26B, 26D, 26E) drivenreciprocally along an axial upstream downstream path of travel throughthe downstream fluid flow passage (22A, 22B, 22D, 22E) by a downstreamactuator (30A, 30B, 30D, 30E) between a gate open and a gate closedposition,

at least one fluid property sensor (50A, 50B, 50D, 50E) mounted withinthe system such that the fluid property sensor detects, at a downstreamdetection time, a selected property of a fluid flow front (5R, 5L) ofthe fluid material (4) flowing downstream through the mold cavity at atrigger location within the cavity disposed between the first gate (24C)and at least one selected downstream gate (24A, 24B, 24D, 24E),

the fluid property sensor (50A, 50B, 50D, 50E) sending a first signalindicative of the downstream detection time to a controller (60),

the controller (60) receiving the first signal and including a set ofinstructions that instruct the actuator (30A, 30B, 30D, 30E) of thevalve associated with the at least one selected downstream gate (24A,24B, 24D, 24E) to open the gate on a first injection cycle bywithdrawing the valve pin (26A, 26B, 26D, 26E) from the gate closedposition at an instruction time (X), the instruction time on the firstinjection cycle comprising a predetermined open gate target time (X)following the downstream detection time,

wherein the valve associated with the at least one selected downstreamgate further includes a position sensor that detects an actual open gatetime (A) upon withdrawal of the valve pin from the at least one selecteddownstream gate (24A, 24B, 24D, 24E), the position sensor sending asignal indicative of the actual open gate time (A) to the controller,

the controller receiving the signal from the first position sensor andincluding a set of instructions that automatically determines anadjusted instruction time (X′) for use on a subsequent injection cycle,wherein the instructions that automatically determines comprisesdecreasing the time of instruction to the valve pin to open on thesubsequent injection cycle by an adjustment time equal to any delay intime (Y) between the predetermined open gate target time (X) and theactual open gate time (A).

In such a system, the instructions can be performed continuously over aplurality of subsequent injection molding cycles, and wherein theadjusted instruction time (X′) of a subsequent cycle is determined byincreasing or decreasing the adjusted instruction time of a prior cycleby an adjustment time equal to the difference in time between the actualopen gate time of the prior cycle and the actual open gate time of apresent subsequent cycle.

Such system can further comprise one or more additional fluid propertysensors (50A, 50B, 50D, 50E) associated with each downstream gatemounted within the system such that each additional fluid propertysensor detects, at a downstream detection time, the selected property ofthe flow front of the fluid material flowing downstream at an additionaltrigger location within the cavity disposed between the first gate andeach downstream gate,

each additional fluid property sensor sending a corresponding firstsignal indicative of the respective downstream detection time to thecontroller,

the controller receiving the corresponding first signals and including aset of instructions that instruct the actuator of the valve associatedwith each downstream gate to open the gate by withdrawing acorresponding valve pin from the gate closed position at a respectivepredetermined open gate target time (X) following the respectivedownstream detection time.

Each of the one or more downstream valves typically includes anassociated position sensor that detects an actual open gate time (A)upon withdrawal of the valve pin from the associated downstream gate,each associated position sensor sending a signal indicative of thesensed position of each corresponding valve pin to the controller, thecontroller receiving the signals from each of the associated positionsensors,

the controller including a set of instructions that automaticallydetermines an adjusted instruction time (X′) for use on a subsequentinjection cycle, wherein the instructions that automatically determinescomprises decreasing the time of instruction to the respective valve pinto open on a subsequent injection cycle by an adjustment time equal toany delay in time (Y) between the predetermined open gate target time(X) and the actual open gate time (A).

The fluid property sensor is a temperature sensor and the sensedproperty is temperature or change in temperature.

In another aspect of the invention there is provided a method ofoperating an injection molding system (10) for initiating flow of afluid material into multiple gates of a mold cavity (18) during aninjection cycle, wherein the system includes:

a first selected valve comprising a first fluid flow passage (22C)having a first gate (24C) to the cavity, a first valve pin (26C) drivenreciprocally along an axial upstream downstream path of travel throughthe first flow passage (22C) by a first actuator (30C) between gate openand gate closed positions,

one or more downstream valves, each downstream valve comprising adownstream fluid flow passage (22A, 22B, 22D, 22E) having a downstreamgate (24A, 24B, 24D, 24E) to the cavity (18) disposed downstream of thefirst gate (24C), a downstream valve pin (26A, 26B, 26D, 26E) drivenreciprocally along an axial upstream downstream path of travel throughthe downstream fluid flow passage (22A, 22B, 22D, 22E) by a downstreamactuator (30A, 30B, 30D, 30E) between a gate open and a gate closedposition the method comprising:

detecting, at a downstream detection time, a select property of a flowfront of the fluid material flowing downstream at a trigger positionwithin the cavity disposed between the first gate (24C) and at least oneselected downstream gate (24A, 24B, 24D, 24E) wherein,

instructing the actuator (30A, 30B, 30D, 30E) of the valve associatedwith the at least one selected downstream gate (24A, 24B, 24D, 24E), ora control valve for that actuator, to withdraw the valve pin (26A, 26B,26D, 26E) from the gate closed position at an instruction time (X)comprising a predetermined open gate target time (X) following thedownstream detection time,

detecting, at an actual open gate time (A), withdrawal of the valve pin(26A, 26B, 26D, 26E) from the at least one selected downstream gate,

determining an adjusted instruction time (X′), for use on a subsequentinjection cycle, wherein the determining step comprises decreasing thetime of instruction to the valve pin to open on a subsequent injectioncycle by an adjustment time equal to any delay in time (Y) between thepredetermined open gate target time (X) and the actual open gate time(A).

Such a method can further comprise operating the system described aboveto cause the actuator of the valve associated with the at least oneselected downstream gate to withdraw the valve pin from the gate closedposition at the adjusted instruction time (X′) following the downstreamdetection time.

In such a method, the determining step is preferably performedcontinuously over a plurality of subsequent injection molding cycles,and wherein the subsequent adjusted instruction time (X′) is determinedby increasing or decreasing the adjusted instruction time of a priorcycle by an adjustment time equal to the difference in time between theactual open gate time of the prior cycle and the actual open gate timeof the present cycle.

In another aspect of the invention there is provided a method ofinitiating flow of fluid material (4) into a gate (24) of a mold cavity(18) during an injection molding cycle,

the cavity having multiple gates including an upstream gate (24 u) and adownstream gate (24 d), each gate having an associated actuator (30) andvalve pin (26), and the valve pin being driven by the actuator between agate closed position (GCP) and a gate open position (GOP),

a position sensor (40) associated with the downstream gate that detectswithdrawal of the valve pin from the gate closed position toward thegate open position at an actual open gate time (A) and generates anopening signal (S_(O)) indicative of the actual open gate time (A),

a cavity sensor (50) that detects a selected physical condition ofarrival (DA) of a flow front (5) of the fluid material at a cavitysensor location (CSL) disposed within the mold cavity between theupstream and downstream gates and generates a detection arrival signal(S_(DA)) indicative of a time (t_(DA)) of the detected arrival of theflow front;

a controller (60), communicating with the cavity sensor (50), positionsensor (40) and actuator (30),

the method comprising steps of:

during a first injection molding cycle:

-   -   detecting, by the cavity sensor (50), the arrival of the flow        front of the fluid material in the cavity at the cavity sensor        location (CSL) and transmitting the detection signal (S_(DA)) to        the controller (60),    -   the controller (60) generating and transmitting to the        downstream actuator (30 d), or a control valve that controls the        downstream actuator, a gate open signal (S_(GO)) at an        instruction time comprising a predetermined open gate target        time (X) subsequent to the detected arrival time (t_(DA)),    -   sensing, by the position sensor (40 d) of the downstream gate,        withdrawal of the valve pin and transmitting the opening signal        (S_(O)) to the controller (60) with the actual open gate time        (A), the actual open gate time (A) being indicative of a delay        time (Y) between the predetermined open gate target time (X) and        the actual open gate time (A),    -   the controller (60) generating an adjusted instruction time (X′)        comprising the predetermined open gate target time (X) minus the        delay time (Y), and during a subsequent injection molding cycle,    -   after the cavity sensor (50) detects and transmits the detection        signal (S_(DA)) to the controller (60), the controller        transmitting to the downstream actuator (30 d) or its control        valve a gate open signal (S_(GO)) at the adjusted instruction        time (X′) subsequent to the detected arrival time (t_(DA)).        10. The method of claim 9 comprising:

providing, for a plurality of adjacent upstream and downstream gatepairs (24 u, 24 d), the associated position and cavity sensors (40, 50)and performing the method steps during the first and subsequentinjection molding cycles, and

wherein the subsequent adjusted instruction time (X′) is determined byincreasing or decreasing the adjusted instruction time of a prior cycleby an adjustment time equal to the difference in time between the actualopen gate time of the prior cycle and the actual open gate time of thepresent cycle.

The upstream gate can be a first upstream gate (24 u 1) that initiatesan initial flow front (5 i) into the cavity (18).

The actuator (30 u 1) associated with the first upstream gate (24 u 1)typically receives a start of cycle signal (S_(SC)) from the controller(60) or an injection molding machine (12) and in response thereto theactuator (30 u 1) initiates opening movement of the valve pin for thefirst upstream gate (24 u 1).

The cavity sensor (50) is typically a temperature sensor.

The position sensor (40) is typically a hall effect sensor.

The position sensor (40) can sense movement of an actuator piston (32)that drives the valve pin (26).

The actuator (30) typically includes a solenoid valve (36) that isactivated by the gate open signal (S_(GO)) to drive the valve pin (28)from the gate closed position (GCP) toward the gate open position (GOP).

The actuator (30) can be an electronic actuator and the position sensor(40) can be an encoder.

The method steps can be performed continuously over a plurality ofsubsequent injection molding cycles, and wherein the subsequent adjustedinstruction time (X′) is determined by increasing or decreasing theadjusted instruction time of a prior cycle by an adjustment time equalto the difference in time between the actual open gate time of the priorcycle and the actual open gate time of the present cycle.

19. A method according to any the foregoing claims 9-18 wherein thecavity sensor (50) continuously detects a selected physical condition atthe cavity sensor location (CSL) and transmits a continuous outputsignal to the controller (60) indicative of the detected physicalcondition.

The position sensor (40) can continuously detect a position of the valvepin (26) and transmits a continuous output signal to the controller (60)indicative of the detected position.

The position sensor (40) can comprise a switch that only detects theinitial opening of the valve pin and transmits the opening signal to thecontroller (60).

21. A method according to any the foregoing claims 9-20 wherein thecavity (18) includes a plurality of upstream and downstream gate pairs(24 u 1, 24 d 1; 24 u 2, 24 d 2; . . . ) having the associated cavityand position sensors (40-1, 50-1; 40-2, 50-2; . . . ), and the methodsteps are performed for each associated gate pair.

The method steps can be performed until all valve pins (26) are in theopen position and the cavity (18) is filled with the fluid material (4).

The subsequent injection molding cycle can be the immediately followinginjection molding cycle.

Such a method can further comprise performing a trial injection moldingcycle to determine the predetermined open gate target time (X).

The controller (60) can receive the predetermined open gate target time(X) from a computer input device (80) that receives, from a humanoperator, the predetermined open gate target time (X).

The predetermined open gate target time (X) can be derived from a moldfilling simulation.

The controller (60) can generate output signals including, for displayon a human readable display (82), the detected arrival time (t_(DA)) andthe actual open gate time (A).

The controller (60) can receive the predetermined open gate target time(X) from a computer input device (80) that receives, from a humanoperator, the predetermined open gate target time (X).

The generating steps can be automatically executed by an algorithmexecuted by the controller (60).

The controller (60) can access profile data (90) comprising a desiredprofile of valve pin position versus time and the controller generatesand transmits signals to the actuator (30) for adjusting the position orvelocity of the valve pin (26) to approach or match the desired profile.

In another aspect of the invention there is provided apparatus forinitiating flow of fluid material into a gate of a mold cavity during aninjection molding cycle, the apparatus comprising:

a manifold (14) that receives a fluid material (4), the manifold havingor communicating with a delivery channel (15) that delivers the fluidmaterial under an injection pressure to multiple gates (24) of a moldcavity (18), the multiple gates including an upstream gate (24 u) and adownstream gate (24 d), each gate having an associated actuator (30) andvalve pin (26), and the valve pin being driven by the actuator between agate closed position GCP and a gate open position GOP,

a position sensor (40) associated with the downstream gate that sensesinitial opening movement (IOM) of the valve pin from the gate closedposition toward the gate open position as an actual open gate time (A)and generates an opening signal (S_(O)) indicative of the actual opengate time (A),

a cavity sensor (50) that detects a selected physical condition ofarrival (DA) of a flow front of the fluid material at a cavity sensorlocation (CSL) disposed within the mold cavity between the upstream anddownstream gates and generates a detection arrival signal (S_(DA))indicative of a time (t_(DA)) of the detected arrival of the flow front;

a controller (60), communicating with the cavity sensor (50), positionsensor (40) and actuator (30), the controller including instructions forgenerating output signals to the actuator,

wherein, during a first injection molding cycle, the apparatus performssteps of:

detecting, by the cavity sensor (50), the flow front of the fluidmaterial in the cavity at the cavity sensor location (CSL) andtransmitting the detection signal (S_(DA)) to the controller,

the controller (60) generating and transmitting to the downstreamactuator, or a control valve that controls the downstream actuator, agate open signal (S_(GO)) at a predetermined open gate target time (X)subsequent to the detected arrival time (t_(DA)),

sensing, by the position sensor (40), the initial opening movement ofthe valve pin and transmitting the opening signal with to thecontroller, the actual open gate time (A) being indicative of a delaytime (Y) between the predetermined open gate target time (X) and theactual open gate time (A),

the controller generating an adjusted instruction time (X′) thatcomprises the predetermined open gate target time (X) minus the delaytime (Y), and

during a subsequent injection molding cycle, the apparatus performssteps of:

after the cavity sensor (50) detects and transmits the detection signal(S_(DA)) to the controller, the controller (60) transmitting to thedownstream actuator (30 d) or its control valve a gate open signal atthe adjusted instruction time (X′) subsequent to the detected arrivaltime (t_(DA)).

In another aspect of the invention there is provided an injectionmolding system (710) for initiating flow of fluid material (718) intomultiple gates of a mold cavity (770) during an injection molding cycle,the system (710) comprising:

a first selected valve (711) comprising a first fluid flow passage(7115) having a first gate (785) to the cavity, a first valve pin (7112)driven reciprocally along an axial upstream downstream path of travelthrough the first flow passage (7115) by a first actuator (730) betweengate open and gate closed positions,

one or more downstream valves (711 a, 711 b, 711 c), each downstreamvalve comprising a downstream fluid flow passage having a downstreamgate to the cavity (770) disposed downstream of the first gate (785 a),a downstream valve pin (7112 a, 7112 b, 7112 c) driven reciprocallyalong an axial upstream downstream path of travel through the downstreamfluid flow passage (7115 a, 7115 b, 7115 c) by a downstream actuator(730 a, 730 b, 730 c) between a gate open and a gate closed position,

a controller (760) receiving a first signal (708, 795 b), indicative ofa start of injection that feeds the fluid material to the injectionmolding system, the controller (760) including a set of instructionsthat instruct the actuator (730 a, 730 b, 730 c) of the valve associatedwith the at least one selected downstream gate (785 a, 785 b, 785 c) toopen the gate by withdrawing the valve pin (7112 a, 7112 b, 7112 c) fromthe gate closed position at an instruction time (X), the instructiontime comprising a predetermined open gate target time (X) based on thefirst signal,

wherein the valve associated with the at least one selected downstreamgate further includes a position sensor (732) that detects an actualopen gate time (A) upon withdrawal of the valve pin from the at leastone selected downstream gate (785 a, 785 b, 785 c), the position sensor(732) sending a signal indicative of the actual open gate time (A) tothe controller (760),

the controller receiving the signal from the position sensor (732) andincluding a set of instructions that automatically determines anadjusted instruction time (X′) for use on a subsequent injection cycle,wherein the instructions that automatically determines comprisesdecreasing the time of instruction to the valve pin to open on asubsequent injection cycle by an adjustment time equal to any delay intime (Y) between the predetermined open gate target time (X) and theactual open gate time (A).

The instructions can be performed continuously over a plurality ofsubsequent injection molding cycles, and wherein the subsequent adjustedinstruction time (X″) is determined by increasing or decreasing theadjusted instruction time of a prior cycle by an adjustment time equalto the difference in time between the actual open gate time of the priorcycle and the actual open gate time of the present cycle.

The start of injection signal (708) can be transmitted by a controllerof an injection molding machine (715) to the controller (760).

In another aspect of the invention there is provided a methodcomprising:

a controller receiving a first signal, indicative of a start ofinjection or a position of a screw barrel that feeds fluid material toan injection molding system, and transmits to a downstream actuator agate open signal at a predetermined open gate target time (X) based onthe first signal;

a downstream actuator receiving the gate open signal and initiateswithdrawal movement of a downstream valve pin from a downstream gate;

a position sensor detecting actual withdrawal movement of the downstreamvalve pin from the downstream gate and transmits a signal indicative ofthe actual gate open time (A) to the controller;

the controller receiving the signal from the position sensor andgenerates an adjusted instruction time (X′) based on the difference(delay time Y) between the actual gate open time (A) and thepredetermined open gate target time (X), for use in subsequent cycle.

In such a method the steps can be performed continuously over aplurality of subsequent injection molding cycles, and wherein thesubsequent adjusted instruction time (X″) is determined by increasing ordecreasing the adjusted instruction time of a prior cycle by anadjustment time equal to the difference in time between the actual opengate time of the prior cycle and the actual open gate time of thepresent cycle.

In another aspect of the invention there is provided an injectionmolding system (710) for initiating flow of fluid material (718) intomultiple gates of a mold cavity (770) during an injection molding cycle,the system (710) comprising:

a first selected valve (711) comprising a first fluid flow passage(7115) having a first gate (785) to the cavity, a first valve pin (7112)driven reciprocally along an axial upstream downstream path of travelthrough the first flow passage (7115) by a first actuator (730) betweengate open and gate closed positions,

one or more downstream valves (711 a, 711 b, 711 c), each downstreamvalve comprising a downstream fluid flow passage having a downstreamgate to the cavity (770) disposed downstream of the first gate (785 a),a downstream valve pin (7112 a, 7112 b, 7112 c) driven reciprocallyalong an axial upstream downstream path of travel through the downstreamfluid flow passage (7115 a, 7115 b, 7115 c) by a downstream actuator(730 a, 730 b, 730 c) between a gate open and a gate closed position,

a controller (760) receiving a first signal (708, 795 b), indicative ofa start of a position of a barrel screw (716) that feeds the fluidmaterial to the injection molding system, the controller (760) includinga set of instructions that instruct the actuator (730 a, 730 b, 730 c)of the valve associated with the at least one selected downstream gate(785 a, 785 b, 785 c) to open the gate on a first injection cycle bywithdrawing the valve pin (7112 a, 7112 b, 7112 c) from the gate closedposition upon arrival of the barrel screw (716) at a predetermined opengate screw position (OGSP) occurring at an open gate screw position time(OGSPT),

wherein the valve associated with the at least one selected downstreamgate further includes a position sensor (732) that detects an actualopen gate time (A) upon withdrawal of the valve pin from the at leastone selected downstream gate (785 a, 785 b, 785 c), the position sensor(732) sending a signal indicative of the actual open gate time (A) tothe controller (760),

the controller receiving the signal from the position sensor (732) andincluding a set of instructions that automatically determines anadjusted open gate screw position (OGSP′) for use on a subsequentinjection cycle, the instructions that automatically determinescomprising automatically determining the adjusted screw position (OGSP′)to be a position on a subsequent injection cycle that accounts for anydelay in time (Y) on the first injection cycle between the open gatescrew position time (OGSPT) and the actual open gate time (A).

The instructions can be performed continuously over a plurality offurther subsequent injection cycles, wherein the adjusted instructiontime (OGSP′) of a further subsequent injection cycle is determined to bea position that accounts for any delay in time (Y) between the open gatescrew position time (OGSPT) on a prior cycle and the actual open gatetime (A) of the further subsequent injection cycle.

Each of the one or more downstream valves typically includes anassociated position sensor that detects an actual open gate time (A)upon withdrawal of the valve pin from the associated downstream gate,each associated position sensor sending a signal indicative of thesensed position of each corresponding valve pin to the controller, thecontroller receiving the signals from each of the associated positionsensors,

the controller including a set of instructions that accounts for thedelay in time (Y) by decreasing the length of travel of the screw on asubsequent injection cycle to a shortened adjusted open gate screwposition (OGSP′) relative to the open gate screw position (OGSP) thatcompensates for the delay in time (Y).

In such an apparatus the position of the screw (OGSP, OGSP′) istypically detected by a sensor that detects rotational or linearposition of the screw at a single position or at multiple positions orcontinuously along all positions.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the various embodiments of theinvention may be better understood by referring to the followingdescription in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic partial sectional view of one embodiment of aninjection molding system for performing a sequential valve gatingprocess, in accordance with one embodiment of the invention;

FIG. 2 is a schematic view of the FIG. 1 apparatus at the beginning ofan injection sequence, in which a first (center) gate has opened tostart a flow of fluid material into a mold cavity;

FIG. 3 is a schematic view of the FIG. 1 apparatus, later in thesequence (after FIG. 2 ), showing a first set of two downstream gatesadjacent opposite sides of the center gate now open with fluid materialfrom each of the two downstream gates also entering (flowing into) themold cavity;

FIG. 4 is a schematic view of the FIG. 1 apparatus, still later in thesequence (after FIG. 3 ), showing a second set of two downstream gates,each of the second set adjacent and downstream of a respective one ofthe first set of downstream gates, now open with fluid material fromeach of the second set (along with fluid material from the center gateand the first set) flowing into the cavity;

FIG. 5 is a flow chart showing one embodiment of a sequence of stepsaccording to one method embodiment of the invention;

FIG. 6 is a flow chart of another embodiment of a sequence of stepsaccording to another method embodiment of the invention;

FIG. 7 is a schematic view of an apparatus for implementing the methodof FIG. 6 ; and

FIG. 8 illustrates an example computing device.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention are now described withreference to the drawings. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of one or more implementations of the presentinvention. It will be evident, however, that the present invention maybe practiced without these specific details. In other instances,well-known structures and devices are shown in block diagram form inorder to facilitate describing the present invention.

Sequential Valve Gating Apparatus and Method

FIG. 1 is a schematic view of a plastic injection molding apparatus forimplementing a sequential valve gating process according to oneembodiment of the invention. The injection molding system (IMM) 10includes an injection molding machine 12, a manifold 14, a mold 16having a mold cavity 18, a valve gating system 20 including a pluralityof nozzles 21 that feed the single mold cavity, an actuator 30associated with each nozzle, and a controller 60 that activates thevalve gating system. The system also includes a plurality of downstreamcavity sensors 50, and valve gating position sensors 40, utilized in thepresent embodiment as described below. Signals from the cavity sensors50 are transmitted to a junction box 70 enroute to controller 60, whilesignals from position sensors 40 are transmitted to a junction box 72enroute to controller 60.

More specifically, the injection molding machine 12 feeds a heatedmolten fluid material 4 (e.g. a plastic or polymer-based fluid material)through a main inlet 13 to a distribution channel 15 of manifold 14. Thedistribution channel commonly feeds the fluid material to five separatenozzles 21A, 21B, 21C, 21D, 21E, which in turn all commonly feed into acommon cavity 18 of a mold 16 to make one molded part. Each nozzle isactuated by an associated actuator 30A, 30B, 30C, 30D and 30Erespectively, wherein each actuator drives an associated valve pin 26A,26B, 26C, 26D and 26E in the associated nozzle, the respective valve pinbeing driven reciprocally along an axial upstream and downstream path oftravel through a flow passage 22A, 22B, 22C, 22D and 22E in therespective nozzle, between a downstream gate closed position (GCP) andan upstream gate open position (GOP), and vice versa, between the GOPand the GCP. Each actuator has a piston 32A-32E controlled by a solenoidvalve for moving the associated valve pin between the GOP and GCPpositions. The position sensors 40A-40E detect the position of thepiston 32, and thus the position of the associated valve pin 26, betweenGOP and GCP.

The start of an injection cycle is triggered by a “Start of InjectionSignal” 8 sent from IMM 12 to the controller 60. The controller thensends output signals 9 to solenoid valves 11 that drive each actuator.In this example, the first gate to open during an injection moldingcycle is the central (also referred to as a first upstream) gate 24C ofcentral nozzle 21C controlled by actuator 30C and arranged so as to feedinto cavity 18 at an entrance point (gate 24C) that is disposed at aboutthe longitudinal center of the elongated mold cavity 18. As shown inFIG. 1 and subsequent figures, a first adjacent set of lateraldownstream nozzles 21B, 21C, disposed laterally adjacent either side ofthe central nozzle feed fluid material 4 to downstream gates 24B and 24Ddisposed laterally an equal distance on either side of the central gate24C. A second set of lateral downstream nozzles 21A, 21E, downstream ofthe first pair of lateral nozzles 21B and 21D, feed fluid material 4into the mold cavity at gate locations 24A and 24E respectively that aredownstream of the center gate 24C and downstream of the gates 24B and24E of the first lateral set of nozzles.

As illustrated in FIGS. 2-4 and described further below, the injectioncycle is a cascade process where injection is effected in a sequencefrom the center nozzle 21C and then at a later predetermined time fromthe first set of downstream nozzles 21B, 21D, and at a still laterpredetermined time from the second set of further downstream nozzles21A, 21E. As shown in FIG. 2 , the injection cycle is started by firstopening the center gate 24C into mold cavity 18 by withdrawing thedistal tip 27C of the center valve pin 26C from the gate 24C andallowing fluid material 4 to flow outwardly from nozzle passage 22C intothe cavity and form a flow stream 5 moving in opposing lateraldirections from the center gate 24C, creating two opposing flow fronts5R (moving laterally to the right toward next downstream gate 24D) and5L (moving laterally to the left toward next downstream gate 24B). Inaccordance with the present embodiment, a plurality of cavity sensors50B, 50C, 50D and 50E are disposed in or adjacent to the mold cavity 18for detecting the arrival of flow fronts 5R and 5L at each respectivecavity sensor location (CSL) (also referred to as a trigger location).More specifically, between each adjacent set of upstream and downstreamnozzle gates, there is disposed a respective cavity sensor for detectingwhen the flow front reaches the vicinity of the downstream gate,referred to herein as a detection arrival DA. As described later below,when this occurs, a signal is sent to the controller 60 to cause asequence of subsequent actions that initiate withdrawal of the valve pinof the associated downstream gate (by sending a signal to the downstreamactuator to open the downstream valve gate at a predetermined open gatetarget time (X), specific to that gate, as well as monitoring anddetection of the actual open gate time (A) of withdrawal of the valvepin from the downstream gate and generating a signal (sent to controller60) indicative of actual open gate time (A). The controller thendetermines whether there is a difference between the predetermined opengate target time (A) and the actual open gate time (A). This difference,referred to as a delay time (Y), can be used to modify the instructiontime for initiating withdrawal of the downstream valve pin from thedownstream gate during a next or subsequent injection cycle, with a goaltoward minimizing or eliminating the time difference.

More specifically, FIG. 2 shows the opposing flow fronts 5R and 5Lmoving toward the first set of lateral downstream gates 24D and 24B.When the flow front 5R is adjacent to or at the cavity sensor 50Dassociated with downstream gate 24D (of nozzle 21D), the cavity sensordetects a selected physical condition (e.g., temperature) that signalsarrival of the flow front of the fluid material at the cavity sensorlocation CSL (50D) located between the upstream gate 24C and thedownstream gate 24D, and generates a detection arrival signal S_(DA)indicative of the time t_((DA)) of the detected arrival of the flowfront 5R. This detection arrival signal is sent to controller 60 toinitiate an instruction signal to actuator 40D (associated with nozzle21D) to cause subsequent withdrawal of the distal tip of valve pin 24Dfrom gate 24D at a predetermined open gate target time (X) subsequent tothe detected arrival time t_((DA)). A similar series of events occursfor the opposing flow front 5L as it reaches the cavity sensor 50B andgenerates a detection arrival signal for initiating a subsequentwithdrawal of valve pin 26B from gate 24B.

FIG. 3 shows the sequential injection process at a later time in which,following the opening of the first set of lateral downstream gates 24Dand 24B whereby fluid material 4 from those gates joins the initialstream (from center gate 24C) to form a combined flow stream 5, theopposing flow fronts 5R and 5L have moved past gates 24D and 24B and arenow moving towards the respective second lateral set of downstreamnozzle gates 24E and 24A. The respective flow fronts 5R and 5L will bedetected by a second set of cavity sensors 50E and 50A associated withthe second set of downstream gates 24E and 24A (of nozzles 21E and 21A)for similarly triggering initiation of withdrawal of the respectivevalve pins 26E and 26A from the second set of downstream valve gates 24Eand 24A. The detection will occur as the flow fronts move from thelocations shown in FIG. 2 further downstream to a time the flow frontarrivals are detected by the cavity sensors 50E and 50A. Similarly, thisdetection will case the sensors 50E and 50D to generate and send signalsS_(DA) controller 60 with times indicative of the detected arrivalt_((DA)), thereby initiating the controller to send gate open signalsS_(GO) to the respective actuators 30E and 30A associated with therespective nozzles 21E and 21A to open the respective gates bywithdrawing the respective valve pins 26E and 26A at instruction times(X) comprising the predetermined open gate target times (X) for therespective nozzles. The positions of these valve pins will be monitoredby position sensors 40E and 40A for the actual open gate time (A) uponwithdrawal of the respective valve pins from the gates, the positionsensors sending the controller signals indicative thereof whereby thecontroller can then compare (A) and (X) to determine whether a timingdifference exists. If the actual open gate is different from thepredetermined open gate target time, the instruction time (X) can beautomatically adjusted for use in a subsequent injection cycle in anattempt to eliminate any difference between the instruction time and theactual gate open time during the subsequent injection cycle.

The above process will continue until all nozzles are open and themolded part is filled. Typically, the valve pins all remain open untilthe end of a packing period, and then the valve gates are closed by asignal from the injection machine.

Thus, in accordance with the present invention, adjustments to theinstruction time (X) for use in a subsequent cycle can be made wherethere is a detected difference (delay Y) between the predetermined opengate target time (X) (desired opening time) and actual open gate time(A). Modification of the instruction time (X) can be automaticallyaccomplished by the controller and utilized in the next cycle. Stillfurther, if a valve pin fails to open or is slow in opening, the systemmay provide an alarm that is activated by such an event.

By way of example, the predetermined open gate target time (X) may be0.3 seconds, and the actual open gate target time (A) may be 0.4seconds, meaning there is a difference or delay Y of 0.1 seconds(0.4−0.3=0.1). The adjusted instruction time X¹ is then determined to beX−Y, namely 0.3−(0.4−0.3)=0.2 seconds. On the next or subsequent cyclethe modified instruction time (X′) will be 0.2 seconds.

It has been found that triggering based on the flow front detection,instead of the time or screw position, can significantly enhance thequality of the molded parts. It can also substantially reduce the set-uptime and reduce the need for highly experienced operators. Thetriggering process can be used to automatically adjust the open gateinstruction time (X) when melt viscosity changes, from one cycle to thenext. The actual valve pin opening times can be displayed on a userinterface (e.g., a computing device 80 with a display and user input asshown in FIG. 1 ), thus enabling an operator to monitor the performanceof the sequential process and make manual adjustments (e.g., to thetiming, temperature, pressure or other system parameters) if desired.

FIG. 5 is a flowchart showing a sequence of steps 501-505 according toone method embodiment comprising:

-   -   cavity sensor, located between upstream and downstream gates,        detects arrival of flow front and transmits detection signal to        controller (step 501)    -   controller receives detection signal and transmits to downstream        actuator a gate open signal at predetermined open gate target        time (X) (step 502)    -   downstream actuator receives gate open signal and initiates        withdrawal movement of downstream valve pin from downstream gate        (step 503)    -   position sensor detects actual withdrawal (movement) of        downstream valve pin from downstream gate and transmits signal        with actual gate open time (A) to controller (step 504)    -   controller receives signal with actual gate open time (A) and        generates an adjusted instruction time (X′) based on the        difference (delay time Y) between the actual gate open time (A)        and predetermined open gate target time (X), for use in        subsequent cycle (step 505).

The following timing sequence illustrates one embodiment of theinvention:

Timing Sequence Time Event t_(0a) start of cycle a t_(1a) predeterminedstart injection time for center gate to open t_(2a) cavity sensorlocated between center gate and first downstream gate detects flow frontt_(3a) predetermined open gate target time for first downstream gate toopen t_(4a) actual open gate time first downstream gate opens (based onopening movement of valve pin) . . . t_(0b) start of subsequent cycle bt_(1b) predetermined start injection time for center gate to open t_(2b)cavity sensor located between center gate and first downstream gatedetects flow front t_(3b) Adjusted instruction time for first downstreamgate to open (based on difference between predetermined open gate targettime t_(3a) and actual open gate time t_(4a) in cycle a) . . .

The preselected condition (e.g., physical property) of the fluid thatthe cavity sensor detects (senses) may be from example, pressure ortemperature. As used herein, the detection (sensing) includes one ormore of a numerical value or a change in value of the property.

The position sensor may be any of various known sensors such as a halleffect sensor as described in Tan et al., U.S. Pat. No. 9,144,929 issuedSep. 29, 2015 entitled “Apparatus and Method of Detecting a Position ofan Actuator Position,” assigned to Synventive Molding Systems, thedisclosure of which is incorporated by reference as if fully set forthin its entirety herein. Alternatively, the position sensor may be anencoder (e.g., for use with an electronic actuator).

The actuation system as shown comprises a fluid driven actuator 30. Apreferred fluid driven valve system comprises a fast acting linear forcemotor driven proportional valve that regulates the flow of either gas orliquid to the actuator 30, namely either a pneumatic or hydraulicsystem. A fast acting fluid control valve system is described in detailin PCT/US2014/31000 and in U.S. Pat. No. 5,960,831, the disclosures ofboth of which are incorporated herein by reference can be used in theapparatuses described herein particularly where pneumatic valve controlsystems are preferred for the particular application.

Alternatively, an electronic (electrically powered) actuator system,having an electric motor rotor interconnected to the valve pin, may beused. See for example the electrically powered actuator systemsdisclosed in U.S. Pat. Nos. 6,294,122, 9,492,960, and 9,498,909, thedisclosures of which are incorporated by reference as if fully set forthin their entirety herein.

Another Embodiment

In another embodiment, instead of triggering based on detecting the flowfront in the cavity, the triggering is based on a start of injectioncycle or screw position in the barrel. FIG. 6 illustrates a methodaccording to this embodiment, and FIG. 7 illustrates an apparatus thatcan be used in this embodiment.

FIG. 6 is a flowchart showing a sequence of steps 601-604 according toone method embodiment comprising:

-   -   controller receives a first signal, indicative of a start of        injection or a position of a barrel screw that feeds the fluid        material to the injection molding system, and transmits to a        downstream actuator a gate open signal at a predetermined open        gate target time (X) based on the first signal (step 601)    -   downstream actuator receives gate open signal and initiates        withdrawal movement of downstream valve pin from downstream gate        (step 602)    -   position sensor detects actual withdrawal (movement) of        downstream valve pin from downstream gate and transmits signal        indicative of the actual gate open time (A) to controller (step        603)    -   controller receives signal indicative of actual gate open        time (A) and generates an adjusted instruction time (X′) based        on the difference (delay time Y) between the actual gate open        time (A) and predetermined open gate target time (X), for use in        subsequent cycle (step 604).

FIG. 7 shows one system embodiment 710 of the invention comprised of aninjection machine 715 that feeds melt-able injection material that isconverted from solid form 717 into molten or liquid flowing fluidmaterial form 718 within the barrel 719 of the machine 715 by a screw716. The screw 716 is controllably rotated at a selected rate such thatthe helical threads 714 of the screw 716 drive the molten fluid material718 downstream under a controllably variable pressure and controllablyvariable amount of fluid into a fluid distribution channel 765 of a hotrunner or manifold 760 depending on the rate and degree of rotation ofthe screw 716. The fluid distribution channel 765 can commonly feed intothe downstream flow passage(s) 7115 of the injection nozzle(s) 7110 ofone or more of multiple valve gates or valves 711, 711 a, 711 b, 711 c.

Each valve 711, 711 a, 711 b, 711 c is comprised of an actuator 730 anda mounted nozzle 7110. Each nozzle 7110 of each valve 711, 711 a, 711 b,711 c routes the molten fluid material 718 that is received from asingle common source (fed from barrel 719, through an inlet 719 b thatinterconnects the barrel to the manifold, and then through the commonmanifold channel 765 through a nozzle passage 7115 to and ultimatelythrough a respective gate 785, 785 a, 785 b, 785 c of the nozzlesassociated with each valve 711, 711 a, 711 b, 711 c to a single cavity780 of a mold 770. Here, each of the multiple valves 711, 711 a, 711 b,711 c inject into the mold cavity 780 (typically in a cascade orsequential manner) during the course of a single injection cycle aspreviously described (with respect to the prior embodiment of FIG. 1 ).

The system 710 employs a sensor 790 that senses or detects a linear orrotational position of the barrel screw 716, at a start or initialportion of the injection cycle such that detection of initial movementor a selected position of the screw 716 by the sensor 790 can be used todefine the start or start time of an injection cycle. The sensor 790,which in this embodiment is shown as detecting the rotational positionof a motor 791 that drivably rotates the screw 716, the rotationalposition of the motor 791 corresponding to the rotational or linearposition of the screw. A predetermined open gate screw position OGSP isselected by the user. The position sensor 790 detects the predeterminedopen gate screw position OGSP and sends a signal 795 indicative of thatposition (or the time OGSPT associated with detecting such position) tothe controller 760. The signal 795 that is sent to controller 760 may bea continuous real time signal indicative of the screw position along itsentire course of rotation or path of travel. Detection by the positionsensor 790 of the original predetermined open gate screw position OGSPand any subsequently automatically adjusted open gate screw positions(OGSP′) are used as triggers by the controller to instruct thedownstream valves 711 a, 711 b, 711 c and their associated gates to openon the first and subsequent injection cycles.

The controller 760 includes instructions that use the received signal795 as a control value that controls one or more valve pins 7112 of theone or more valves 711, 711 a, 711 b, 711 c such that the one or morevalve pins 7112 are driven through an upstream path of travel beginningfrom the gate closed position to open the respective valve gate, at apredetermined open gate target time (X) for the respective gate. In oneembodiment, the valve 711 may be designated as the first upstream gateto open, followed by subsequent openings of the remaining gates 785 a,785 b and 785 c each at their respective predetermined open gate targettimes (X) as triggered by the start signal 795. In another embodiment,the IMM sends a start of injection signal 708 that is used as thecontrol value and trigger to open the respective gates, instead of thescrew position signal 795. In this later embodiment, the screw positionsensor 790 and signal 795 are not required.

FIG. 7 illustrates the components of one valve 711 in detail. For easeof explanation, each valve 711 a, 711 b, 711 c is typically comprised ofthe same components as described with reference to valve 711, each valvebeing commonly fed by the injection fluid material 718 flowing frombarrel 719 through inlet 719 b to the manifold and further flowingthrough downstream manifold channel 765. Manifold channel 765 is shownand referred to as one example of a common fluid flow channel.

As shown, the distal end of nozzle 7110 has a gate 785 (here theupstream gate to the mold cavity 780) that is controllably openable andcloseable by a valve pin 7112 to start and stop the flow of material 718through gate 785. Such controlled gate opening and closing is effectedby controlled reciprocal upstream and downstream movement A of valve pin7112 that is controllably driven by a pneumatic actuator 730 that is inturn controllably driven most preferably by a fast acting linear forcemotor or valve 720. The downstream distal tip end of the valve pin 7112initially closes the gate 785 at the start of an injection cycle. Whenan injection cycle is initiated the valve pin 7112 is withdrawn upstreamopening the upstream gate 785 and allowing the molten fluid material 718to flow through the gate 785 into the cavity 780 of the mold 770. Thedownstream gates 785 a, 785 b, 785 c are then open in sequence at eachof their predetermined open gate times. Valve pin position sensors 732,similar to position sensors in FIG. 1 , are mounted on each actuator 730for each valve 711, and used to detect the actual open gate time (A) ofthe respective downstream gate which is then compared with thepredetermined open gate target time (X) for the respective downstreamgate, in order to determine an adjustment time equal to any delay intime (Y) between the predetermined open gate time (X) and the actualopen gate time (A). See the discussion in the prior embodiment of FIGS.1-5 regarding use of the valve pin position sensors 40 and determinationof an adjusted instruction time (X′) for use on a subsequent injectioncycle.

Returning to the FIG. 7 embodiment, at time zero of the injection cycle(start of injection signal received from the IMM 715 or screw positionsignal 795 received from the sensor 790), the first upstream valve 711is initially opened (with all other downstream valves 711 a, 711 b, 711c remaining closed) and the screw 716 is simultaneously started up tobegin rotating and thus increasing the pressure in barrel 719 a, inlet719 b from an initial zero up to a desired level. At a later time thesecond valve pin associated with the second valve 711 a is initiallywithdrawn from its associated gate. With the first and second valves711, 711 a now open and third and fourth valves 711 b, 711 c stillclosed, the pressure is increased as the screw continues to injectinjection fluid into the system until the pressure reaches a desiredpressure when the pin associated with the third valve 711 b is openedfrom its associated gate. Now with the first and second and third valves711, 711 a, 711 b open and valve 711 c still closed, the pressure isincreased as the screw continues to inject injection fluid into thesystem until the pressure reaches a desired pressure at which time thepin associated with the fourth valve 711 c is withdrawn from tisassociated gate. With all four valves now open and the screw underconstant power drive force, the pressure continues to rise up to a finalconstant or steady pressure.

In embodiments where the controller 760 controls all of the multiplevalve gates 711, 711 a, 711 b, 711 c during an injection cycle, thecontroller 760 includes a pin sequence instruction that can instruct andexecute the opening and upstream pin withdrawal movement of eachseparate valve 711, 711 a, 711 b, 711 c in any preselected timedsequence.

The actuators associated with gates 711, 711 a, 711 b, 711 c typicallycomprise a pneumatic or hydraulic actuator or can also comprise anelectric actuator, the controller 760 being adapted to control the drivemechanism for each such kind of actuator. In the case of a pneumaticallyor hydraulically driven actuator, the drive mechanism is an electricallydrivable mechanism interconnected to a fluid flow control valve similarto valve 720. In the case of an electric actuator the drive mechanism istypically an electric motor that is controllably drivable by anelectronic controller 760.

Each separate valve 11, 11 a, 11 b, 11 c can feeds into a single cavity780 of a single mold or can each feed separately into separate cavitiesof separate molds (not shown for valves 11 a, 11 b, 11 c).

In order to reduce or eliminate the visibility of the lines or blemishesin the final molded part, a fast acting motor 20 that acts as theactuator for a valve can be employed.

The controller 760 instructs the actuators 730 et al. associated withthe gates via signals 210, 210 a, 210 b, 210 c generated by an algorithmcontained in the electronic controller 760 to withdraw the pinsassociated with the valves 711, 711 a, 711 b, 711 c at an upstreamwithdrawal velocity that can be controlled along any portion of theupstream or downstream travel path or stroke of the valve pins.

In a typical embodiment, the first valve 711 is initially opened withall other downstream valves 711 a, 711 b, 711 c being closed untilinstructed to sequentially open at sequentially subsequent times asdescribed herein.

Computing Device

FIG. 6 illustrates an example computing system architecture 1000 whereinthe components of the system 1000 are in communication with each otherusing a connection 1005. Connection 1005 can be a physical connectionvia a bus, or direct connection into processor 1010 such as in a chipsetarchitecture. Connection 1005 can also be a virtual connection,networked connection, or logical connection. The connection can be wiredor wireless (such as a Bluetooth connection).

In some cases, the system 1000 is a distributed system, wherein thefunctions described with respect to the components herein can bedistributed within a datacenter, multiple datacenters, geographically,etc. In some embodiments, one or more of the described system componentsrepresents many such components each performing some or all of thefunction for which the component is described. In some embodiments, thecomponents described herein can be physical or virtual devices.

Example system 1000 includes at least one processing unit (CPU orprocessor) 1010 and a connection 1005 that couples various systemcomponents including the system memory 1015, such as read only memory(ROM) 1020 and random access memory (RAM) 1025 to the processor 1010.The system 1000 can include a cache of high-speed memory 1012 connecteddirectly with, in close proximity to, or integrated as part of theprocessor 1010.

The processor 1010 can include any general purpose processor and ahardware service or software service, such as service 1 1032, service 21034, and service 3 1036 stored in storage device 1030, configured tocontrol the processor 1010 as well as a special-purpose processor wheresoftware instructions are incorporated into the actual processor design.The processor 1010 may essentially be a completely self-containedcomputing system, containing multiple cores or processors, a bus, memorycontroller, cache, etc. A multi-core processor may be symmetric orasymmetric.

To enable user interaction with the computing device 1000, an inputdevice 1045 can represent any number of input mechanisms, such as amicrophone for speech, a touch-sensitive screen for gesture or graphicalinput, keyboard, mouse, motion input, speech and so forth. An outputdevice 1035 can also be one or more of a number of output mechanismsknown to those of skill in the art. In some instances, multimodalsystems can enable a user to provide multiple types of input tocommunicate with the computing device 1000. The communications interface1040 can generally govern and manage the user input and system output.There is no restriction on operating on any particular hardwarearrangement and therefore the basic features here may easily besubstituted for improved hardware or firmware arrangements as they aredeveloped.

Storage device 1030 can be a non-volatile memory and can be a hard diskor other types of computer readable media which can store data that areaccessible by a computer, such as magnetic cassettes, flash memorycards, solid state memory devices, digital versatile disks, cartridges,random access memories (RAMs) 1025, read only memory (ROM) 1020, andhybrids thereof.

The storage device 1030 can include code that when executed by theprocessor 1010, causes the system 1000 to perform a function. A hardwareservice that performs a particular function can include the softwarecomponent stored in a computer-readable medium in connection with thehardware components, such as the processor 1010, bus 1005, output device1035, and so forth, to carry out the function.

For clarity of explanation, in some instances the present technology maybe presented as including individual functional blocks includingfunctional blocks comprising devices, device components, steps orroutines in a method embodied in software, or combinations of hardwareand software.

Any of the steps, operations, functions, or processes described hereinmay be performed or implemented by a combination of hardware andsoftware services, alone or in combination with other devices. In someembodiments, a service can be software that resides in memory of aclient device and/or one or more servers of a content management systemand perform one or more functions when a processor executes the softwareassociated with the service. In some embodiments, a service is aprogram, or a collection of programs that carry out a specific function.In some embodiments, a service can be considered a server. The memorycan be a non-transitory computer-readable medium.

In some embodiments the computer-readable storage devices, mediums, andmemories can include a cable or wireless signal containing a bit streamand the like. However, when mentioned, non-transitory computer-readablestorage media expressly exclude media such as energy, carrier signals,electromagnetic waves, and signals per se.

Methods according to the above-described examples can be implementedusing computer-executable instructions that are stored or otherwiseavailable from computer readable media. Such instructions can comprise,for example, instructions and data which cause or otherwise configure ageneral purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.Portions of computer resources used can be accessible over a network.The computer executable instructions may be, for example, binaries,intermediate format instructions such as assembly language, firmware, orsource code. Examples of computer-readable media that may be used tostore instructions, information used, and/or information created duringmethods according to described examples include magnetic or opticaldisks, solid state memory devices, flash memory, USB devices providedwith non-volatile memory, networked storage devices, and so on.

Devices implementing methods according to these disclosures can comprisehardware, firmware and/or software, and can take any of a variety ofform factors. Typical examples of such form factors include servers,laptops, smart phones, small form factor personal computers, personaldigital assistants, and so on. Functionality described herein also canbe embodied in peripherals or add-in cards. Such functionality can alsobe implemented on a circuit board among different chips or differentprocesses executing in a single device, by way of further example.

The instructions, media for conveying such instructions, computingresources for executing them, and other structures for supporting suchcomputing resources are means for providing the functions described inthese disclosures.

Although a variety of examples and other information was used to explainaspects within the scope of the appended claims, no limitation of theclaims should be implied based on particular features or arrangements insuch examples, as one of ordinary skill would be able to use theseexamples to derive a wide variety of implementations. Further andalthough some subject matter may have been described in languagespecific to examples of structural features and/or method steps, it isto be understood that the subject matter defined in the appended claimsis not necessarily limited to these described features or acts. Forexample, such functionality can be distributed differently or performedin components other than those identified herein. Rather, the describedfeatures and steps are disclosed as examples of components of systemsand methods within the scope of the appended claims.

Claim language reciting “at least one of” refers to at least one of aset and indicates that one member of the set or multiple members of theset satisfy the claim. For example, claim language reciting “at leastone of A and B” means A, B, or A and B.

While specific embodiments of the present invention have been shown anddescribed, it will be apparent that many modifications can be madethereto without departing from the scope of the invention. Accordingly,the invention is not limited by the foregoing description.

What is claimed is:
 1. A method of operating an injection molding systemfor initiating flow of a fluid material into multiple gates of a moldcavity during an injection cycle, wherein the system includes: a firstselected valve comprising a first fluid flow passage having a first gateto the cavity, a first valve pin driven reciprocally along an axialupstream downstream path of travel through the first flow passage by afirst actuator between gate open and gate closed positions, one or moredownstream valves, each downstream valve comprising a downstream fluidflow passage having a downstream gate to the cavity disposed downstreamof the first gate, a downstream valve pin driven reciprocally along anaxial upstream downstream path of travel through the downstream fluidflow passage by a downstream actuator between a gate open and a gateclosed position the method comprising: detecting, at a downstreamdetection time, a select property of a flow front of the fluid materialflowing downstream at a trigger position within the cavity disposedbetween the first gate and at least one selected downstream gatewherein, instructing the actuator of the valve associated with the atleast one selected downstream gate, or a control valve for thatactuator, to withdraw the valve pin from the gate closed position at aninstruction time (X) comprising a predetermined open gate target time(X) following the downstream detection time, detecting, at an actualopen gate time, withdrawal of the valve pin from the at least oneselected downstream gate, determining an adjusted instruction time (X′),for use on a subsequent injection cycle, wherein the determining stepcomprises decreasing the time of instruction to the valve pin to open ona subsequent injection cycle by an adjustment time equal to any delay intime (Y) between the predetermined open gate target time (X) and theactual open gate time (A).
 2. A method according to claim 1 furthercomprising operating the system described above to cause the actuator ofthe valve associated with the at least one selected downstream gate towithdraw the valve pin from the gate closed position at the adjustedinstruction time (X′) following the downstream detection time.
 3. Amethod according to claim 1 wherein the determining step is performedcontinuously over a plurality of subsequent injection molding cycles,and wherein the subsequent adjusted instruction time (X″) is determinedby increasing or decreasing the adjusted instruction time of a priorcycle by an adjustment time equal to the difference in time between theactual open gate time of the prior cycle and the actual open gate timeof the present cycle.
 4. A method according to claim 1 the multiplegates of the cavity including an upstream gate and a downstream gate,each gate having an associated actuator and valve pin, and the valve pinbeing driven by the actuator between a gate closed position (GCP) and agate open position (GOP), a position sensor associated with thedownstream gate that detects withdrawal of the valve pin from the gateclosed position toward the gate open position at an actual open gatetime (A) and generates an opening signal (S_(O)) indicative of theactual open gate time (A), a cavity sensor that detects a selectedphysical condition of arrival (DA) of a flow front of the fluid materialat a cavity sensor location (CSL) disposed within the mold cavitybetween the upstream and downstream gates and generates a detectionarrival signal (S_(DA)) indicative of a time (t_(DA)) of the detectedarrival of the flow front; a controller, communicating with the cavitysensor, position sensor and actuator, the method comprising steps of:during a first injection molding cycle: detecting, by the cavity sensor,the arrival of the flow front of the fluid material in the cavity at thecavity sensor location (CSL) and transmitting the detection signal(S_(DA)) to the controller, the controller generating and transmittingto the downstream actuator, or a control valve that controls thedownstream actuator, a gate open signal (S_(GO)) at an instruction timecomprising a predetermined open gate target time (X) subsequent to thedetected arrival time (t_(DA)), sensing, by the position sensor of thedownstream gate, withdrawal of the valve pin and transmitting theopening signal (S_(O)) to the controller with the actual open gate time(A), the actual open gate time (A) being indicative of a delay time (Y)between the predetermined open gate target time (X) and the actual opengate time (A), the controller generating an adjusted instruction (X′)time comprising the predetermined open gate target time (X) minus thedelay time (Y), and during a subsequent injection molding cycle, afterthe cavity sensor detects and transmits the detection signal (S_(DA)) tothe controller, the controller transmitting to the downstream actuatoror its control valve a gate open signal (S_(GO)) at the adjustedinstruction time (X′) subsequent to the detected arrival time (t_(DA)).5. A method according to claim 4 comprising: providing, for a pluralityof adjacent upstream and downstream gate pairs, the associated positionand cavity sensors and performing the method steps during the first andsubsequent injection molding cycles, and wherein the subsequent adjustedinstruction time (X′) is determined by increasing or decreasing theadjusted instruction time of a prior cycle by an adjustment time equalto the difference in time between the actual open gate time of the priorcycle and the actual open gate time of the present cycle.
 6. A methodaccording to claim 4 wherein the upstream gate is a first upstream gatethat initiates an initial flow front into the cavity.
 7. A methodaccording to claim 4 wherein the actuator associated with the firstupstream gate receives a start of cycle signal (S_(SC)) from thecontroller or an injection molding machine and in response thereto theactuator initiates opening movement of the valve pin for the firstupstream gate.
 8. A method according to claim 4 wherein the cavitysensor is a temperature sensor.
 9. A method according to claim 4 whereinthe position sensor is a hall effect sensor.
 10. A method according toclaim 4 wherein the position sensor senses movement of an actuatorpiston that drives the valve pin.
 11. A method according to claim 4wherein the actuator includes a solenoid valve that is activated by thegate open signal (S_(GO)) to drive the valve pin from the gate closedposition (GCP) toward the gate open position (GOP).
 12. A methodaccording to claim 4 wherein the actuator is an electronic actuator andthe position sensor is an encoder.
 13. A method according to claim 4wherein the method steps are performed continuously over a plurality ofsubsequent injection molding cycles, and wherein the subsequent adjustedinstruction time (X′) is determined by increasing or decreasing theadjusted instruction time of a prior cycle by an adjustment time equalto the difference in time between the actual open gate time of the priorcycle and the actual open gate time of the present cycle.
 14. A methodaccording to claim 4 further comprising performing a trial injectionmolding cycle to determine the predetermined open gate target time (X).15. A method according to claim 4 wherein the method steps are performedcontinuously over a plurality of subsequent injection molding cycles,and wherein the subsequent adjusted instruction time (X′) is determinedby increasing or decreasing the adjusted instruction time of a priorcycle by an adjustment time equal to the difference in time between theactual open gate time of the prior cycle and the actual open gate timeof the present cycle.
 16. A method according to claim 6 wherein thecavity sensor continuously detects a selected physical condition at thecavity sensor location (CSL) and transmits a continuous output signal tothe controller indicative of the detected physical condition.
 17. Amethod according to claim 6 wherein the position sensor continuouslydetects a position of the valve pin and transmits a continuous outputsignal to the controller indicative of the detected position.
 18. Amethod according to claim 6 wherein the position sensor is a switch thatonly detects the initial opening of the valve pin and transmits theopening signal to the controller.
 19. A method according to claim 6wherein the cavity includes a plurality of upstream and downstream gatepairs having the associated cavity and position sensors, and the methodsteps are performed for each associated gate pair.
 20. A methodaccording to claim 6 wherein the method steps are performed until allvalve pins are in the open position and the cavity is filled with thefluid material; and/or wherein the subsequent injection molding cycle isthe immediately following injection molding cycle.
 21. A methodaccording to claim 6 further comprising performing a trial injectionmolding cycle to determine the predetermined open gate target time (X).22. A method according to claim 6 wherein the controller receives thepredetermined open gate target time (X) from a computer input devicethat receives, from a human operator, the predetermined open gate targettime (X); and/or wherein the predetermined open gate target time (X) isderived from a mold filling simulation; and/or wherein the controllergenerates output signals including, for display on a human readabledisplay, the detected arrival time (t_(DA)) and the actual open gatetime (A).
 23. A method according to claim 6 wherein the controllerreceives the predetermined open gate target time (X) from a computerinput device that receives, from a human operator, the predeterminedopen gate target time (X); and/or wherein the generating steps areautomatically executed by an algorithm executed by the controller;and/or wherein the controller accesses profile data comprising a desiredprofile of valve pin position versus time and the controller generatesand transmits signals to the actuator for adjusting the position orvelocity of the valve pin to approach or match the desired profile.